| 摘要 |
PURPOSE:To enhance a wafer position detecting speed and to detect the defect of a chip by emitting laser pulses incident on four corners of each chip of a semiconductor wafer, comparing the reflected light with a reference signal and deciding whether this chip is measured or not. CONSTITUTION:A probe card 4 has a metal stylus for a signal line and a metal stylus for detecting a wafer position. Four laser lights 101-104 from a laser light source 8 are respectively reflected on reflecting plates 111-114, reflected on the surface of a chip to be measured through a measuring window of the card 4, and mechanically positioned to pass the route of incident light converters 131-134 from the plates 121-124. A timing measuring unit 9 generates a pulse for measuring and discriminating. The reflected lights from the positions of the chips to be measured are respectively compared by comparators 141-144 with a reference value 17, and an OR gate 15 detects the light of different reflectivity. The probe which receives the output rises a wafer stationary base 6 to measure or moves to next chip to be measured as remained at standby position. |
